In industry, porous inorganic materials have been widely used as catalysts and catalyst carriers. These porous materials generally include amorphous porous materials, crystalline molecular sieves and modified layered materials. Minute difference in the structure between any two materials may indicate significant difference in properties like catalytic performance and adsorbing ability therebetween, and further difference in available parameters used to characterize same, such as morphology, specific surface area or pore size.
The structure of a molecular sieve is specifically confirmed by the X-ray diffraction pattern (XRD), while the X-ray diffraction pattern (XRD) is determined by X-ray powder diffraction with a Cu—K α-ray source and a Ni filter. Different molecular sieves have different characterizing XRD patterns. Known molecular sieves, like A-Type Zeolite, Y-Type Zeolite, MCM-22 molecular sieve and so on, have their characterizing XRD patterns respectively.
At the same time, two molecular sieves, if sharing the same characterizing XRD pattern but comprising different combination of skeleton elements, will be identified as different molecular sieves. For example, TS-1 molecular sieve (U.S. Pat. No. 4,410,501) and ZSM-5 molecular sieve (U.S. Pat. No. 3,702,886), share the same characterizing XRD pattern but comprise different combination of skeleton elements. Specifically, TS-1 molecular sieve comprises Si and Ti as the skeleton elements, exhibiting a catalytic oxidation ability, while ZSM-5 molecular sieve comprises Si and Al as the skeleton elements, exhibiting an acidic catalytic ability.
Further, two molecular sieves, if sharing the same characterizing XRD pattern and the same combination of skeleton elements but with different relative amounts of the skeleton elements, will be identified as different molecular sieves as well. For example, Zeolite X (U.S. Pat. No. 2,882,244) and Zeolite Y (U.S. Pat. No. 3,130,007), share the same characterizing XRD pattern and the same combination of skeleton elements (Si and Al), but with different relative amounts of Si and Al. Specifically, Zeolite X has a Si/Al molar ratio of less than 1.5, while Zeolite Y has a Si/Al molar ratio of greater than 1.5.
Among the known molecular sieves, molecular sieves having the SFE structure share the same XRD pattern as illustrated in the following table. The typical molecular sieve having the SFE structure is SSZ-48 molecular sieve (having a chemical composition of 40<XO2/Y2O3<100), which was sythensized by the Chevron company on the year of 1997 (U.S. Pat. No. 6,080,382).
2θ (°)(a)d-spacing (Å)(b)Relative intensity (I/I0 × 100)6.5013.59w-s7.9811.07s-vs9.369.45m11.277.85w-m20.024.43s22.653.92vs24.133.69vs26.453.37w-m27.923.19w-m35.952.50m(a)±0.3°,(b)changed with 2θ.
J. Phys. Chem. B 1999, 103, 8245-8250 reported a process for producing the SSZ-48 molecular sieve, wherein SiO2/B2O3=63 and the crystallization duration is 49 days. Microporous and Mesoporous Materials 52 (2002) 19-28 reported a process for producing the SSZ-48 molecular sieve, wherein SiO2/B2O3=42 and the crystallization duration is 60 days, or SiO2/B2O3=50 and a crystallization duration of 42 days.